1. Field of Invention
This invention relates generally to implantable medical devices, and more specifically to a device used for treatment of stress incontinence
2. Description of Prior Art
Incontinence is a major health problem in the United States and accounts for approximately $ 10 billions for our annual health care costs. It is estimated that over 10 million individuals suffer from urinary incontinence, 60-70% of which are females.
Although there are several types of female incontinence, stress incontinence or stress and urge incontinence is the most common. Stress incontinence is triggered by sudden tensing of the abdominal muscles which occurs during coughing, laughing, and certain physical activities. It is caused by abnormalities in the anatomy of the bladder outlet structures, the sphincter and the urethra.
This problem is most pronounced in the elderly female population due to prolapse of the uterus which distorts the geometry of the bladder neck resulting in a 30% incontinence rate in women over 60 years of age. This problem causes acute embarrassment and inhibits physical and social activity.
Many methods and devices for managing incontinence are currently available;
One of the available methods is the use of an artificial, inflatable urinary sphincter, generally comprises an inflatable cuff, a fluid reservoir and a pump. The artificial sphincter is surgically implanted so that the cuff surrounds the urethra and the pump is placed in an accessible location such as scrotum in male or labia majora in female. The cuff is normally filled with fluid so as to constrict the bulbar urethra and prevent the bladder from emptying. When the user wishes to empty his bladder, the pump is squeezed, which forces fluid out of the cuff and into the reservoir, thereby deflating the cuff and opening the urethra. Although relatively effective, the artificial inflatable urinary sphincter has some serious shortcomings. The main difficulty with such a sphincter is that the constant encircling pressure applied to the bulbar urethra results in unacceptable urethral erosion and scarring because the sphincter encircles the urethra and substantially restricts blood flow therein. After several years of use, such a sphincter may result in sever damage to the urethra.
U.S. Pat. No. 5,520,606 date May 28, 1996, describes an apparatus comprises an inflatable, urethra-compressing balloon having a tissue engaging surface positioned between the urethra on a side of the urethra opposite the pubic bone. A patient having the apparatus surgically implanted therein may selectively advance hydraulic fluid between the reservoir and the balloon so as to inflate or deflate the balloon and prevent or allow bladder emptying respectively.
Many procedures involving urethro-vesical elevation, have been devised over the years to cure stress incontinence. Some of those are described in U.S. Pat. No. 5,112,344 and U.S. Pat. No. 5,019,032.
A sling procedure is disclosed in U.S. Pat. No. 5,013,292 in which a method is described by implanting a sling-like anchoring device in the skin above the symphysis pubis to adjust the urethro vesical angle. An implantable sphincter system utilizing lifting means is described in U.S. Pat. No. 5,518,504 date May 21, 1996 in which an actuating device is operably connected to the lifting and lowering device, and a pump capable of being volitionally operated is in fluid communication with the actuating device to provide a pressurized flow of fluid into the actuating device.
Other devices disclosed in prior arts rely mainly on urethral occlusion; U.S. Pat. No. 5,090,424, U.S. Pat. No. 5,082,006, U.S. Pat. No. 5,417,226 date May 23, 1995.
Intra vaginal devices to compress the urethra are also described in many old patents and recently in U.S. Pat. No. 5,611,768.
Up to the present, there remains a need for an apparatus which maintain continence without damaging the tissue of the bladder, urethra, or surrounding areas. A need for a device that allow the maximum use of the normal remaining function of the urethral sphincter and to be activated spontaneously and only temporarily when it is needed (when the intra-abdominal pressure rises above a certain level that causes the incontinence), and deactivated spontaneously when it is not needed,